Systems for venous occlusion for the treatment of venous insufficiency

ABSTRACT

Methods, devices and systems are described for treating venous insufficiency in which the vein is compressed at least partially along a treatment zone. A system can be provided including an injection device, such as a glue gun, that is operably connected to a delivery catheter that can be advanced across a treatment zone in the vein. The delivery catheter can be used to deliver one, two, or more boluses of media (e.g., cyanoacrylate) to occlude the vein along different spaced-apart sections of the treatment zone. External compression can also be applied to the vein by a compression element, such as a hand or multifunctional ultrasound transducer, to occlude portions of the vein along the treatment zone prior to or during the introduction of the boluses of media.

PRIORITY CLAIM

This application is a continuation of U.S. patent application Ser. No. 14/676,238, filed on Apr. 1, 2015, and claims priority to U.S. patent application Ser. No. 14/676,238 under 35 U.S.C. § 120. U.S. patent application Ser. No. 14/676,238 is a continuation of U.S. patent application Ser. No. 12/710,274, issued as U.S. Pat. No. 9,011,486, filed on Feb. 22, 2010, and claims priority to U.S. patent application Ser. No. 12/710,274 under 35 U.S.C. § 120. U.S. patent application Ser. No. 12/710,274 claims priority under 35 U.S.C. § 119(e) to U.S. Provisional App. Nos. 61/154,322 filed on Feb. 20, 2009 and 61/285,926 filed on Dec. 11, 2009. U.S. patent application Ser. No. 12/710,274 also claims priority under 35 U.S.C. § 120 as a continuation-in-part application of PCT App. No. PCT/US2010/024820 filed on Feb. 19, 2010, which in turn claims priority to U.S. Provisional App. Nos. 61/154,322 filed on Feb. 20, 2009 and 61/285,926 filed on Dec. 11, 2009. Each of application Ser. Nos. 14/676,238, 12/710,274, 61/154,322, 61/285,926, and PCT/US2010/024820 is hereby incorporated by reference in its entirety.

BACKGROUND

Healthy leg veins contain valves that allow blood to move in one direction from the lower limbs toward the heart. These valves open when blood is flowing toward the heart, and close to prevent venous reflux, or the backward flow of blood. When veins weaken and become enlarged, their valves cannot close properly, which leads to venous reflux and impaired drainage of venous blood from the legs. Venous reflux is most common in the superficial veins. The largest superficial vein is the great saphenous vein, which runs from the top of the foot to the groin, where it originates at a deep vein.

Factors that contribute to venous reflux disease include female gender, heredity, obesity, lack of physical activity, multiple pregnancies, age, past history of blood clots in the legs and professions that involve long periods of standing. According to population studies, the prevalence of visible tortuous varicose veins, a common indicator of venous reflux disease, is up to 15% for adult men and 25% for adult women. A clinical registry of over 1,000 patients shows that the average age of patients treated for venous reflux is 48 and over 75% of the patients are women.

Venous reflux can be classified as either asymptomatic or symptomatic, depending on the degree of severity. Symptomatic venous reflux disease is a more advanced stage of the disease and can have a profound impact on the patient's quality of life. People with symptomatic venous reflux disease may seek treatment due to a combination of symptoms and signs, which may include leg pain and swelling; painful varicose veins; skin changes such as discoloration or inflammation; and open skin ulcers.

A primary goal of treating symptomatic venous reflux is to eliminate the reflux at its source, such as, for example, the great saphenous vein. If a diseased vein is either closed or removed, blood can automatically reroute into other veins without any known negative consequences to the patient.

The current non-invasive methods for treatment of reflux in the greater saphenous vein include radiofrequency (RF) ablation, laser endothermal ablation, and sclerotherapy, including foam sclerotherapy. Radiofrequency ablation and laser ablation require tumescent anesthesia which produce both bruising and pain along the inner thigh and upper inner calf for several weeks, and both can have side effects of burns and nerve damage. Radiofrequency ablation and laser ablation also require capital purchases of a radiofrequency device or laser box, often at costs of more than $50,000, in addition to expensive disposal mechanisms. While foam sclerotherapy is relatively non-invasive, it has a high rate of recurrence and potential side effects. All of the methods require wearing compression stockings for 2-4 weeks.

SUMMARY

Disclosed herein is a method of treating a vein, comprising the steps of: advancing a catheter distally across a treatment zone in a vein; creating a first occlusion in the vein at a distal end of the treatment zone; introducing a first bolus of media into the vein against a proximal side of the first occlusion; creating at least a second occlusion in the vein, spaced proximally apart from the first occlusion; introducing a second bolus of media into the vein against a proximal side of the second occlusion; and withdrawing the catheter from the vein.

Also disclosed is a method of treating a vein, comprising the steps of: creating an occlusion in a vein; positioning the distal end of a catheter to define a first volume within the vein between the occlusion and the catheter; and introducing a second volume of media from the catheter into the vein; wherein the second volume is at least about 110% of the first volume.

In another embodiment, disclosed is a method of treating a vein, comprising the steps of creating an occlusion in a vein; positioning the distal end of a catheter within the vein, the catheter having a distal opening and a side wall; and introducing media through the distal opening in a volume sufficient to advance proximally around the catheter between the sidewall of the catheter and the wall of the vein.

Further disclosed is a system for treating a vein, comprising: an injector for delivering a vein-occluding substance into a vein. The injector can be operably connected to a control. The control could, for example, have a dial, button, footpad, or the like operably configured to actuate the injector a preset amount, and could include electronics such as a processor, and/or software. Activation of the control results in the injector delivering a bolus of between about 0.05 mL and 3 mL of the vein-occluding substance into the vein. The system is configured to deliver a plurality of spaced-apart boluses of the vein-occluding substance. Also included in the system is a catheter having a distal opening and a side wall, the catheter configured operably to be connected to the injector, wherein the catheter is configured to advance distally across a treatment zone in the vein. The injector can include a glue gun, which may also include an adapter, which can be as described below. The catheter can include a luer lock for operable connection to the injector. The system can also include a volume of vein-occluding substance, such as between about 1 mL to 20 mL of vein-occluding substance in some embodiments. The vein-occluding substance could be cyanoacrylate, and further include a compression element configured to externally compress the vein. The control can be configured to actuate the injector to introduce media through the distal opening in a volume sufficient to advance proximally around the catheter between the sidewall of the catheter and the wall of the vein. The system can also include an occluder comprising a frame portion and a barrier portion, examples of which are described further in detail below.

In another embodiment, disclosed is a system for treating a vein, that includes a catheter comprising a proximal opening, a distal opening, and a sidewall, the catheter configured to deliver a vein-occluding substance within a vein, the catheter having a length sufficient to extend from a distal superficial leg vein to the superficial femoral vein junction; a sheath configured to house the catheter at least partially therethrough, the sheath having a length of from about 25 cm to about 100 cm and an inside diameter of from about 3 French to about 7 French; and an injector carrying a vein-occluding substance, the injector operably connectable to the catheter and comprising a control, wherein actuation of the control causes injection of a predetermined volume of vein-occluding substance, wherein the predetermined volume of vein-occluding substance is between about 0.05 mL and 0.5 mL.

In yet another embodiment, discloses is a catheter comprising a proximal opening, a distal end having a distal opening, and a sidewall, the catheter configured to deliver a vein-occluding substance within a vein, the catheter having a length sufficient to extend from a distal superficial leg vein to the superficial femoral vein junction; a sheath configured to house the catheter at least partially therethrough, the sheath having a length of from about 25 cm to about 100 cm; and an injector carrying a vein-occluding substance, the injector operably connectable to the catheter and comprising a control, wherein actuation of the control when the distal end of the catheter is positioned within the vein proximal to an occlusion in the vein causes injection of a predetermined volume of vein-occluding substance into the catheter and out the catheter distal opening, wherein the predetermined volume is sufficient to advance the vein-occluding substance proximally around the catheter between the sidewall of the catheter and the wall of the vein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-11 schematically illustrate a method for occluding a vein, such as the great saphenous vein, using a vein-occluding substance and an imaging tool, according to one embodiment of the invention.

FIGS. 12-16 schematically illustrate a method for occluding a vein, such as the great saphenous vein, according to another embodiment of the invention.

FIGS. 17-21E schematically illustrate methods for occluding a vein, such as the great saphenous vein, according to another embodiment of the invention.

FIGS. 22-32 illustrate various views and components of a vein-occluding dispensing system according to some embodiments of the invention.

FIGS. 33-34 schematically illustrate a glue gun and adapter assembly.

FIG. 35 schematically illustrates a front view of a glue gun, according to one embodiment of the invention.

FIG. 36 illustrates schematically major components of a vascular occlusion system, according to one embodiment of the invention.

FIGS. 37A-37D illustrate various views of a vascular occlusion device, according to one embodiment of the invention.

FIGS. 38A-38D illustrate various views of the occlusion device of FIGS. 2A-2D in an expanded configuration.

FIGS. 39A-39B illustrate an embodiment of the frame portion of the delivery device described above in connection with FIGS. 2A-3D with the barrier portion omitted for clarity.

FIG. 40 is a side cross-sectional view of an occlusion device in an expanded configuration and implanted within a vessel, according to one embodiment of the invention.

FIG. 41 is a cross-sectional view of an occlusion device in an undeployed configuration within a delivery catheter, according to one embodiment of the invention.

FIGS. 42-44 illustrate perspective, cross-sectional views of an occlusion device in varying stages of deployment out of a delivery catheter, according to one embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Disclosed herein are systems, methods and devices for the minimally invasive treatment of varicose veins and other medical conditions. When used herein with respect to the device, proximal can refer to toward the access insertion site into a blood vessel, while distal refers to away from the access insertion site and in the direction of the patient. In some embodiments an occlusive device is deployed to block the saphenous vein just distal to the Superficial Femoral Vein Junction (SFJ) and create a flattened shape so the vein can be treated further using either a substance to alter the vein such that blood flow is prevented therein, such as sclerosing solution or medical adhesive. In some embodiments, complete vein closure is the desired clinical result of all treatments to mitigate the effects of venous hypertension caused by retrograde venous flow. The occlusion device and medical adhesive can be delivered through a catheter utilizing a “single stick” method. This approach is designed to produce less pain and fewer skin injections than used in current treatment approaches, as well as to mitigate or eliminate the need for patients to wear uncomfortable compression stockings after treatment.

Vein-Collapsing Methods

Methods to treat venous insufficiency are now described, in which the vein is compressed at least partially along the treatment zone. Doing so can better ensure that the vein is partially or fully collapsed as opposed to merely occluded, depending on the desired clinical result. Not to be limited by theory, collapsing the vein may place two or more luminal surfaces of endothelial cells into opposing contact with each other, stimulating fibrous tissue proliferation and resulting in improved long-term closure of the vein with a lower risk of recanalization and vein re-opening. In some embodiments, a deployment catheter is percutaneously introduced into a vein at an access site, and translumenally distally advanced across a treatment zone within a vein. External compression is applied to collapse the vein distally of the deployment catheter. Then the distal end of the catheter advances to the very beginning of the occluded vein at the proximal side of the occlusion to minimize the “trapped” blood between the catheter and the occluded vein. After a bolus of plug forming media is expressed from the distal end of the catheter, the occlusion at the end of the catheter forces the vein-occluding substance to flow retrograde (proximally) toward the catheter insertion point into the vein and reduce the distal flow force and mixing with blood within the vessel. This method also allows the vein-occluding media to replace any existing blood “trapped” between the catheter and the occluded vein and forms an occlusive plug within the vein while minimizing mixing with the blood. This reduction in mixing can be advantageous in certain embodiments because it can increase the bonding strength between the vein-occluding media and the vein. External compression distally to the treatment zone optionally may be removed, or may remain throughout all or a portion of the procedure. External compression can also occur around the area of the vein where the plug forming media is expressed in order to collapse the vein as noted above. The catheter is thereafter proximally retracted while dispensing a vein occluding substance, either continuously or via discrete boluses spaced apart from the initial bolus at regular or irregular intervals across the treatment zone. External compression can continue proximally where the vein occluding substance is being dispensed in order to ensure collapse of the vein as noted above. The catheter is thereafter withdrawn, and the access site closed using conventional techniques. The method is described in greater detail below.

The vein closure system can enter the vein such as the greater saphenous or lesser saphenous vein or other vessel using fluoroscopy, ultrasound, or other guidance means. A micro-catheter system can be placed over a wire for introduction of an outer catheter or introduction sheath into the vein. In some embodiments, the vein is entered as distal as possible or as clinically relevant in the abnormal vein. In some embodiments, the closure method comprises advancement of an introducing sheath and/or dilator over a guide wire to the sapheno-femoral junction below the anterior-inferior epigastric vein, which in some embodiments, can be approximately 1.5 to 2.5 cm from the sapheno-femoral junction. Following placement of the sheath to this level and optional verification with ultrasound, an inner catheter is introduced through the sheath and is luer-locked or otherwise secured to the sheath to maintain a fixed position with the tip extending approximately 5 cm from the end of the sheath.

In accordance with FIG. 1, the occlusion method comprises providing an injector such as a glue gun 300 that assists in injecting a vein-occluding substance to occlude vessel 400. In some embodiments, the distal end 302 of the glue gun 300 includes a syringe that is operably connected to an inner catheter 204 by a luer lock 602. A sheath or outer catheter 202 surrounds the inner catheter 204, and assists in providing access to a target site within the vessel 400 interior. In some embodiments, the outer catheter 202 is introduced first followed by the inner catheter 204, while in other embodiments, the outer catheter 202 and inner catheter 204 are introduced simultaneously. As shown in FIG. 1, the outer catheter 202 and inner catheter 204 are introduced near the proximal end 402 of the vessel 400 and are directed towards the distal end 401 of the vessel, where the vein-occluding substance will be released. Inone embodiment, at the site of release of the vein-occluding substance, the inner catheter 204 will extend beyond the distal end of the outer catheter 202, such as by between about 3 cm and 7 cm, to prevent any vein-occluding substance from contacting the outer catheter 202.

As shown in FIG. 1, an imaging tool such as an ultrasound transducer 630 can also be provided that could be multifunctional, including guiding one or more catheters, serving as a compression element, and/or identifying areas in the interior of the vessel that may need further occlusion or closure. In some embodiments, the ultrasound transducer 630 can be placed into contact with an external surface of a patient's skin prior to placing the outer catheter 202 and/or inner catheter 204 through the vessel 400. The ultrasound transducer 630 can assist in generating images to help guide one or more catheters to a site where a vein-occluding substance will be introduced. In some embodiments, the ultrasound transducer 630 can also serve as a compression element prior to, during or after introducing a vein-occluding substance to assist in closure of the vessel 400. By serving as a compression element, the ultrasound transducer can help to flatten and/or reduce the size of the vessel 400. In some embodiments, the ultrasound transducer 630 can include a Doppler flow detection capability, and help to identify areas in the interior of the vessel 400 that may need further closure or occlusion and thus, further application of a vein-occluding substance.

When the inner catheter is in position and verified with ultrasound to be in the appropriate position below the sapheno-femoral junction, compression at the sapheno-femoral junction is performed and small amounts of vein occluding substances, including liquid adhesives such as glues including cyanoacrylates, or any substances described elsewhere herein or known in the art, are injected into the vein. The vein can then be collapsed using compression, such as external compression to assist in coapting the vein and adhering the internal walls of the vein to the vein-occluding substance in a solid, permanent bond. In some embodiments, an additional compression device can be provided in addition to the ultrasound transducer or probe (either proximally or distally) to assist in collapsing the vein. In some embodiments, the compression device can be a sequential compression device configured to apply compressive pressure from a compressor against the patient's limb through a flexible pressurized sleeve. The compression can be configured to deliver uniform compression along its length, distal-to-proximal compression in a peristaltic wave or other modes depending on the desired clinical result. In some embodiments, the compressive device could be configured to deliver a pressure of at least about 30, 40, 50, 60, 70, 80, 90, 100, 125, 150, or more mm Hg, or between about 30-150 or 50-100 mm Hg in some embodiments. In some embodiments, an external device delivering energy to create a controlled vasospasm of the vein is used. The energy could be, for example, electrical stimulation, cryotherapy, infrared, visible, or UV light, microwave, RF energy, ultrasound energy, magnetic energy, thermal energy, or a combination of the energy sources.

In accordance with FIG. 2, the tip of the inner catheter 204 is placed at a site adjacent to the blocked or distal end 401 of the vessel 400 with a minimum distance between them. Once the outer catheter 202 and inner catheter are in place, the glue gun 300 can inject a vein-occluding substance 502 that is released from the inner catheter 204. In some embodiments, the inner catheter 204 can release at least 1, 2, 3, 4, 5, 7, 10, 12, 15, 20, or more boluses of vein-occluding media along a treatment site within a vein. For example, in some embodiments, a single continuous flow of vein-occluding media can be introduced across a treatment site, while in other embodiments, multiple spaced-apart boluses of vein-occluding media can be introduced at regular or irregular intervals across a treatment site. In some embodiments, the treatment site can be a total length of between 2 cm and 50 cm, or between about 5 cm and 40 cm in some embodiments. Along the treatment site, one or more boluses of vein-occluding media can be introduced at spaced-apart intervals, such as between every 1 cm and 7 cm, more preferably between every 3 cm and 5 cm. The intervals need not be evenly spaced. Each bolus of media can occlude and treat at least a portion of the treatment site. In some embodiments, a single bolus of media can occlude and treat a length of the vein that is between 0.5 cm to 5 cm, such that at least about 0.5 cm, 1 cm, 2 cm, 3 cm, 4 cm, or 5 cm of the vein can be treated. In other embodiments, the length of the treatment site within the vein will be greater than 5 cm by a single bolus of media. Providing one or more boluses of vein-occluding media, particularly in selected intervals, as described herein advantageously provides a treatment that can be performed with greater control and ease over conventional vein-occluding processes and which can be tailored to specific patients (e.g., having different lengths of treatment zones).

In some embodiments, each bolus of media can have a volume of between 0.01 to 3 cc of a vein-occluding substance (e.g., cyanoacrylate compound), such as between 0.01 cc to 1 cc of a vein-occluding substance. The rate of injection can be controlled manually, or by a mechanical and/or electronic controller configured to release a pre-determined volume of vein-occluding substance at a specified flow rate. While in some embodiments the injection rate can be relatively constant throughout the procedure in some embodiments, in other embodiments, the injection rate can be variable, releasing periodic boluses of vein-occluding substance at specified time and/or distance intervals. In some embodiments, the injection rate is between 0.002 cc/sec and 6 cc/sec, such as between about 0.02 cc/sec and 0.2 cc/sec. Controlling the volume and flow rate of the bolus of media to levels described herein advantageously prevents unnecessary overflow or undertreatment of the media within the vein. In some embodiments, an injector is provided that is configured to precisely deliver a predetermined volume of media, such as between about 0.05 mL and 0.5 mL, or between about 0.1 mL and 0.2 mL, into the vein when a physician actuates a control, such as a button, switch, dial, or foot pedal, for example. In some embodiments, the injector includes a safety feature, such as an electronic lockout that prevents unintended multiple bolus injections of glue within a specified period of time, such as, for example, requires that bolus injections be spaced apart by at least about 0.5, 1, 2, 3, 4, 5 seconds, or more.

In accordance with FIG. 3, once the vein-occluding substance 502 is injected out of the tip of the inner catheter 204, the vein-occluding substance 502 flows against the distal end of the proximal side of the occluded vessel 400 and then reverses flow proximally traveling along the outside of the catheter track while displacing the blood content along the target area of the vessel 400. Then, the outer catheter 202 and inner catheter 204 can be pulled back or withdrawn to target a different site along the vessel 400. For example, the outer catheter 202 and inner catheter 204 can be moved in a direction towards the proximal end 402 of the vessel 400 prior to injecting additional vein-occluding substance 502 into the vessel 400.

In accordance with FIG. 4, an optional compression element, e.g., an operator's hand 640, a sequential compression device, or the ultrasound transducer 630 can be used to apply pressure on the external surface of the patient's body and compress the interior walls of the vessel 400. The optional compression element can be used to compress portions of the vessel prior to, during or after the introduction of the vein-occluding substance. When the compression element compresses portions of the vessel during or after the introduction of the vein-occluding substance, the vessel is compressed against the vein-occluding substance 502, as shown in FIG. 4. This compression assists in occlusion as well as collapse of the vessel. In some embodiments, as additional portions of the vessel are treated with the vein-occluding substance, the target regions can be compressed immediately following, or no more than about 5 minutes, 4 minutes, 3 minutes, 2 minutes, 1 minute, 30 seconds, 15 seconds, or less following injection of the vein-occluding substance in some embodiments.

FIGS. 5-6 illustrate the ultrasound transducer 630 guided or moved from a first location to a second location following injection of the vein-occluding substance 502 at the first site. Once the vein-occluding substance 502 is injected to a targeted site and preferably, once the vein is completely occluded and/or collapsed at that site, the ultrasound transducer 630 can be moved to a second location, e.g., a location closer towards the proximal end 402 of the vessel 400, to assist in collapse of the vessel 400 at a different site. In some embodiments, by moving the ultrasound transducer 630 along the length of the vessel 400 in a proximal direction, the ultrasound transducer can serve as a compression element that provides a compression that follows the length of the vessel 400 in a proximal direction to better ensure collapse of the vessel. In some embodiments, the ultrasound transducer or other external compression element can be moved a distance between the first location to a second location spaced apart between 0.5 cm to 5 cm with respect to the first location. In other embodiments, the ultrasound transducer can be moved a distance between the first location to a second location that is between 3% and 50%, such as between 3% and 20% of the total length of the treatment site. Guiding the ultrasound transducer over a discrete distance advantageously helps to ensure that portions of the treatment site are effectively occluded before guiding the ultrasound transducer over different portions of the treatment site. After moving the ultrasound transducer 630, the glue gun 300 can inject a vein-occluding substance 502 at the different site of the vessel 400, as shown in FIG. 6.

Once the vein-occluding substance 502 is injected into the second site of the vessel 400, a compression element e.g., the hand 640, can once again be used to assist in collapse of the portion of the vessel 400, as shown in FIG. 8. After achieving partial or complete closure of a portion of the vessel 400, the ultrasound transducer 630 can once again be guided or moved along the vessel 400 to different locations to assist in closure or occlusion of the vessel 400, providing a moveable compression element in some instances. With the assistance of the ultrasound transducer 630 and/or additional compression element as described above, which can move along the length of the vessel 400 and serve as a compression element and/or image generator, it is possible to collapse the vessel 400 along the entire treatment length. As shown in FIG. 9, the ultrasound transducer 630 is guided to the second location along the vein 400 to assist in collapse of the vessel 400 at the different location.

The application of the ultrasound probe and/or additional compression device can be repeated at multiple locations along the greater saphenous vein, as shown in FIGS. 10-11, until the vein is partially or entirely co-apted and closed in a flattened state. The inner catheter can then be removed, and a band-aid or other dressing can be placed over the entrance site. In some embodiments, the ultrasound probe can generate images that reconfirm the closure or co-apting of the flattened vein. Once the flattened vein is closed partially or completely, the injector is removed from the access site, and the procedure then is completed. In one embodiment, only a small amount of local anesthesia at the entrance site is used. No tumescent anesthesia is required. No general or conscious sedation is required as the procedure produces no significant heat or other types of damage to surrounding tissues.

While the methods above have been described with the intention of occluding the great saphenous vein, a wide variety of other veins, arteries, lymphatics, or other body lumens, natural or artificial can be occluded as well using systems and devices as disclosed herein. Furthermore, a variety of conditions can be treated with the systems, devices, and methods disclosed herein, for example, venous insufficiency/varicose veins of the upper and/or lower extremities, esophageal varices, gastric varices, hemorrhoidal varices, venous lakes, Klippel-Trenanay syndrome, telangiectasias, aneurysms, arterio-venous malformations, embolization of tumors or bleeding vessels, lymphedema, vascular and non-vascular fistulas, closure of fallopian tubes for sterilization, etc.

In some embodiments, the vein-occluding substance can be injected into the vein using an automated process in order to minimize undesired over-injection or under-injection of the vein-occluding substance, injection at undesired intervals or injection of undesired bolus sizes. For example, the outer catheter member of the catheter can be made easily compressible (e.g., with a thin wall). The column strength needed for catheter placement can thus be supplied predominantly with the inner tube. Once the inner catheter has been withdrawn from the vein, the remaining outer catheter is filled with the vein-occluding substance. The proximal end of the outer catheter just distally of the luer lock, manifold, or other coupling to the vein-occluding substance injector can carry a compression element such as a clamp, parallel rollers, or a slideable element with the catheter extending transversely between two portions of the slideable element. Actuating the compression element will radially compress the outer catheter. An operator can then hold the clamp in place while the catheter is pulled proximally through the clamp. The clamp thus slides, rolls, or otherwise moves along the tube, while the catheter is compressed to precisely express the volume of the catheter as a function of the distance the catheter is withdrawn proximally from the vein.

FIGS. 12-16 schematically illustrate a method for occluding a vein, such as the great saphenous vein, according to one embodiment of the invention. Ultrasonographic vein mapping, contrast venography, or other technique, for example, can be used prior to the occlusion procedure to better visualize a patient's particular vascular anatomy in some embodiments. The entry site is prepped and draped in a sterile fashion, and local anesthesia such as Lidocaine can be provided, although may not be required. First, the vascular system, such as a superficial vein in the foot, ankle, or calf, for example, a dorsal digital vein, intercapitular vein, common digital vein, dorsal venous arch, medial marginal vein, lateral marginal vein, plantar cutaneous venous arch, or a vein of the plantar cutaneous venous network is cannulated, such as percutaneously or alternatively through a cut-down procedure. Any of these veins can also be occluded using the systems and methods described herein. Imaging such as ultrasound or fluoroscopy, for example, can be used for access assistance. A guidewire (not shown) can then be inserted into the vessel. A sheath or introducer, such as a needle, can also be placed to facilitate catheter entry into the appropriate vein. Next, a delivery catheter 200, including inner catheter member and outer catheter member, as well as housing an occlusion device such as described above can be inserted into the vessel as shown in FIG. 12 via, for example, the Seldinger technique over a guidewire. The catheter 200 is then advanced distally into the venous system to a desired location, such as within the great saphenous vein (or small saphenous vein or accessory saphenous vein) as shown in FIG. 13. The inner catheter can then be actuated relative to the outer catheter to deploy an occlusion device 100 to its expanded configuration within the desired location within the vein 400. The occlusion device can in some embodiments include components as described, for example, in U.S. Provisional Application No. 61/154,322, filed on Feb. 20, 2009, and herein incorporated by reference in its entirety, including (but not limited to) those having tissue anchors or bars or other features for engaging vessel walls. In some embodiments, the occlusion device can include components as described with respect to FIGS. 36-44. FIG. 14 illustrates the inner catheter being advanced in preparation to deploy an occlusion device 100. Once desired placement is confirmed, the detachment mechanism such as a suture (not shown) is then actuated to release the occlusion device 100 within the vessel. Deployed anchors on the frame portion of the occlusion device 100, can prevent migration of the occlusion device 100 from the desired location within the vein 400. Next, the inner catheter can be withdrawn, as illustrated in FIG. 15.

After withdrawal of the inner catheter, a vein-occluding substance such as described above can be injected through the outer catheter into the vein 400 proximal to the deployed occlusion device. As illustrated in FIG. 16, the outer catheter can then be withdrawn while the vein-occluding substance continues to be injected, in order to occlude the vein in a proximal direction relative to the occlusion device. The outer catheter can then be fully withdrawn, and an external compression stocking applied, completing the procedure. Percutaneous closure methods can also be utilized in some embodiments. In some embodiments, 0.01 cc to 1 cc of vein-occluding substance, e.g., a cyanoacrylate compound, can be injected over a distance of 0.5 cm to 5 cm of vein, such as at least about 0.5 cm, 1 cm, 2 cm, 3 cm, 4 cm, or 5 cm of vein to be treated. The injection rate can be relatively constant throughout the procedure in some embodiments, or variable, releasing periodic boluses of vein-occluding substance at specified time and/or distance intervals. Withdrawal through the vein to be treated can take place, for example, over a period of 30 seconds to 5 minutes in some embodiments, or about equal to, or less than about 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 minute, 45 seconds, or 30 seconds in some embodiments.

A method of occluding a vein utilizing a vein-occluding substance as an occluding member according to some embodiments will now be described in further detail. First, a catheter can be deployed to a desired location in a tubular structure such as a vein as illustrated and described in connection with FIGS. 12 and 13 above. The vein 400 can then optionally be compressed, either before or after placing the catheter, such as by, for example, external manual compression of the leg or with a tourniquet or other type of compression device at a distal location as shown schematically with arrows in FIG. 17. Next, a vein-occluding substance can be injected at a first location within the vein 400 to serve as an occluder 500, as shown in FIG. 18, to prevent embolization more distally. External compression prior to and at a location just distal to the injection site can advantageously help to prevent migration of the formed in situ occluder 500 prior to polymerization or other fixation process. Compression can also prevent unwanted embolization distally into more central veins, as well as induce retrograde flow of the vein-occluding substance proximally when the vein-occluding substance, upon distal ejection from the catheter, contacts the vein at the point that is collapsed from compression, forcing the vein-occluding substance to flow proximally. In some embodiments, the distance from the exit port on the catheter where the vein-occluding substance is ejected to the area of the vein that is collapsed from compression is no more than about 3 cm, 2.5 cm, 2 cm, 1.5 cm, 1 cm, 0.75 cm, 0.5 cm, 0.25 cm, or less.

The vein-occluding substance serving as an occluder 500 can be, for example, a larger-volume bolus of a vein-occluding substance compared to a volume of vein-occluding substance injected more proximally over a specified period of time and/or length of vein, of which specific ranges are described above. The initial bolus can be at least about 0.1 cc, 0.25 cc, 0.5 cc, 0.75 cc, 1 cc, 1.5 cc, or more in some embodiments, or between about 0.05 mL and about 0.9 mL, between about 0.05 mL and about 0.5 mL, or between about 0.1 mL and about 0.2 mL in other embodiments The initial bolus can be at least about 10%, 25%, 50%, 75%, 100%, 150%, 200%, or more greater than a volume of vein-occluding substance injected more proximally over a similar length of vein.

In addition to, or instead of a large bolus volume of vein-occluding substance as described above, a second vein-occluding substance with different properties than a first vein-occluding substance used to treat the vein more proximally can also be used as an occluder. The second vein occluding substance is deployed first, to form the distal vein block. The first vein occluding substance is then dispensed along the length of the treatment site as the catheter is proximally retracted.

The second vein-occluding substance can be, for example, a glue or other occlusive medium that expands to a greater volume, hardens more rapidly, and/or has a shorter polymerization time relative to the first vein-occluding substance. In some embodiments, the second vein-occluding substance can be partially or completely bioresorbable. If multiple different vein-occluding substances are used, the catheter can be configured to have two or more lumens to accommodate delivery of the different vein-occluding substances. Alternatively the first and second occluding substances can be deployed sequentially via a common lumen.

When the vein-occluding substance serving as a distal occluder hardens such that a plug 500 is formed to completely prevent blood flow distally as shown in FIG. 19, the catheter 200 can be withdrawn and the same or a different vein-occluding substance 502 as described above can be injected along the length of the vein segment to be treated to occlude the rest of the vein 400 to be treated while the catheter is withdrawn partially, and fully proximally as shown in FIGS. 20-21, respectively. As illustrated in FIG. 21, in some embodiments, 2, 3, 4, or more veins (that may be in some cases a branch of the first vein) can be treated during the procedure using a single puncture, or with 2, 3, 4, or more punctures.

Thus, in accordance with one implementation of the present invention, a deployment catheter 200 is percutaneously introduced into a vein at an access site, and translumenally distally advanced across a treatment zone within a vein. External compression, such as manual compression, is applied to collapse the vein distally of the deployment catheter and create a first occlusion. A bolus of plug forming media is expressed from the distal end of the catheter against a proximal side of the first occlusion, to form an occlusive plug 500 within the vein. External compression optionally may be removed, or may remain throughout the procedure. The catheter 200 is thereafter proximally retracted while dispensing a vein occluding substance 502 across the treatment zone, either continuously as a long stream, or intermittently at spaced apart intervals, where a second occlusion in the vein can be created, spaced apart from the first occlusion, and then a second bolus of media is introduced against the proximal side of the second occlusion External compression may be applied proximally, anywhere along the length of the vein, to ensure complete filling of the vein with the vein occluding substance 502. In some embodiments, a second, third, or more boluses of plug-forming media are progressively released into the vein more proximally at desired intervals, and external compression can be applied just distal to the point in which the catheter releases the plug forming media as described above. The catheter 200 is thereafter withdrawn, and the access site closed using conventional techniques.

FIG. 21A illustrates a vein 400 that is compressed distally at point 440 to create a first occlusion, such as with external compression. Also shown is catheter 200 with distal end 201. After the creation of an occlusion 440 in a vein, a first volume V1 within the vein 400 can be defined between the distal end 201 of the catheter 200 and the occlusion 440, as illustrated in FIG. 21B. Media having a second volume V2, such as in a bolus, can then be injected from the distal end 201 of the catheter 200 into the vein 400. In some embodiments, the second volume V2 (of the media injected) is at least about 100%, 105%, 110%, 120%, 125%, 130%, 140%, 150%, 175%, 200%, 250%, or more of the first volume V1 (of the vein in between the occlusion and the distal end of the catheter), such that a proximally advancing meniscus of media V2 passes proximally past the distal end 201 of the catheter 200, as illustrated in FIG. 21C. The catheter 200 is then withdrawn proximally, as illustrated in FIG. 21D, and a second more proximal occlusion 440′ can be created, such as via external compression. Media can then be injected to create a volume of media V2′ greater than the volume within the vein 400 between the distal end 201 of the catheter 200 and the occlusion 440′, as illustrated in FIG. 21E. The process can then be repeated for a total of at least 2, 3, 4, 5, 6, 7, 8, 9, 10, or more times depending on the desired clinical result.

In some embodiments, an occlusion in a vein can be created as described herein. A deployment catheter having a distal opening and side wall is provided. The distal end of the deployment catheter can be positioned within the vein at the desired location. Media can then be introduced through the distal opening in a volume sufficient to advance proximally around the catheter between the sidewall of the catheter and the wall of the vein. In some embodiments, the volume sufficient to advance proximally around the catheter between the sidewall of the catheter and the wall of the vein is at least about 0.05 mL, 0.1 mL, 0.2 mL, 0.3 mL, 0.5 mL, 0.7 mL, 0.8 mL, 1 mL, 1.5 mL, 2 mL, 3 mL, or more.

The distal plug 500 may be formed by a bolus of the same material as used for the vein occluding substance 502. Alternatively, the distal plug 500 may be formed from a material that polymerizes more rapidly than vein occluding substance 502, or solidifies through a mechanism other than polymerization to form an occlusive plug. Plug 500 may alternatively be formed by a self-expanding preformed material, such as a foam or woven or non-woven fiber based material, which may be displaced distally from the catheter such as by distally advancing a push wire, or utilizing the pressure of vein occluding substance 502. The self-expanding foam or other plug material 500 may be a bioabsorbable material, so that no long term implant is left behind in the body.

Proximal retraction of the deployment catheter 200 may be accomplished in either a steady, continuous fashion, or in an intermittent, stepped manner. Similarly, extrusion of vein occluding substance 502 may be accomplished in a continuous manner as the catheter 200 is proximally retracted. Alternatively, vein occluding substance 502 may be dispensed in a plurality of bolus ejections along the length of the treatment zone, spaced apart by a predetermined or clinically determined distance. Spacing between adjacent injected volumes of vein occluding substance 502 may be at least about 0.5 cm, at least about 1 cm, at least about 2 cm, and, in some implementations, at least about 4 cm. This procedure minimizes the total volume of injected vein occluding substance 502, while providing a plurality of distinct bonding points along the length of the treatment zone.

Also disclosed herein is a method of obliterating a hollow structure, such as a vein, including the steps of reducing an interior cross-sectional area of the hollow structure near the obliterating site by applying a pressure to an exterior of the hollow structure; and placing a catheter in the hollow structure and advancing it to the obliterating site, where the obliterating site is next to the reduced cross-sectional area. A medical adhesive can then be injected at the obliterating site. The interior cross-sectional area of the medical adhesive at the obliterating site can then be reduced by compressing an exterior of the hollow structure to form an occlusion in the hollow structure. Compression can be achieved, for example, via an imaging probe such as an ultrasound transducer, manual pressure, or a harness. The medical adhesive can then solidify, forming an occlusion in the hollow structure. The method can also include the step of identifying an obliterating site prior to reducing an interior cross-sectional area of the hollow structure. In some embodiments, the catheter is removed from the obliterating site before compression.

With any of the methods and devices described herein, a wide variety of vein-occluding substances can be used. In some embodiments, the substance can include an adhesive such as cyanoacrylate, e.g., 2-octyl cyanoacrylate, and/or a sclerosing agent such as hypertonic saline, sodium tetradecyl sulfate, chromated glycerol, tetracycline, talc, bleomycin, or polydocanol. In some embodiments, a cyanoacrylate can be an aliphatic 2-cyanoacrylate ester such as an alkyl, cycloalkyl, alkenyl or alkoxyalkyl 2-cyanoacrylate ester. The alkyl group may have from 1 to 16 carbon atoms in some embodiments, and can be a C1-C8 alkyl ester or a C1-C4 alkyl ester. Some possible esters include the methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, pentyl, hexyl, cyclohexyl, heptyl, octyl, 2-methoxyethyl and 2-ethoxyethyl esters of cyanoacrylic acid. Other adhesives that can be used include a biological glue such as a bovine serum albumin-gluteraldehyde combination (e.g., BIOGLUE, Cryolife, Atlanta, Ga.), PVA, Biogard, collagen, fibrinogen, fibronectin, vitronectin, laminin, thrombin, gelatin, mixtures thereof, or other biocompatible adhesives. In some embodiments, a foam generated from, for example, one or more of the above components can be used to enhance ablation and closure of the vein. The viscosity and air bubble mixture can also be controlled while taking into account the desired clinical result.

In one embodiment, the chosen adhesive will not produce a significant thermal effect or significant local tissue abnormal effect, but rather produces an initial vessel co-aption/adhesion which will withstand physiological venous pressures within the immediate post-procedure period. Since the adhesive will not produce a significant thermal reaction, no tumescent anesthesia is needed. In some embodiments, the chosen adhesive induces an inflammatory reaction which scars. The inflammatory reaction can be followed by permanent closure of the abnormal greater or less saphenous vein. In some embodiments, the chosen adhesive is hardened after the first few moments (e.g., seconds or minutes) of application and therefore, compression stockings may not be required. With the chosen adhesive, there can be minimal or no danger to surrounding nerves or tissue. While the amount of chosen adhesive delivered to a target site in a vessel will vary depending on the size of the vessel itself, in some embodiments, the amount of adhesive or other vein-occluding substance delivered in a single injection can be between about 0.05 mL and about 0.9 mL, between about 0.05 mL and about 0.5 mL, or between about 0.1 mL and about 0.2 mL in other embodiments. In some embodiments, the amount delivered in a single injection could be more than about 0.4 mL, 0.6 mL, 0.8 mL, 0.9 mL, 1 mL, or more. In some embodiments, the amount delivered in a single injection could be less than about 0.8 mL, 0.6 mL, 0.4 mL, 0.3 mL, 0.2 mL, 0.1 mL, 0.05 mL, or less.

In some embodiments, the cyanoacrylate preparation will contain any additives necessary to impart the desired properties to the preparation as viscosity, color, X-ray opacity, etc. Certain examples of additives such as thickening agents and polymerization inhibitors are discussed further below.

In some embodiments, the chosen adhesive can also be mixed with a thickening agent, including various cyanoacrylate polymers, cyanoacrylate oligmers and biocompatible polymers. The biocompatible polymers can include, for example, PLA, PLLA, PGA, PCL, PDLLA, PLDGA, PMMA, PET, nylon, PE, PP, or PEEK, and in some embodiments, the biocompatible polymers are soluble in a cyanoacrylate monomer. In some embodiments, the thickening agent can comprise glucose, sugar, starch or hydrogel. In some embodiments, the thickening agent can also comprise various particulates, ranging in size between about 0.001 microns to 100 microns. The particulates can be provided in dry solid form and can disperse throughout a liquid adhesive to thicken the adhesive prior to use. In some embodiments, the particulate comprises any of the biocompatible polymers above, such as PLA, PLLA, PGA, PCL, PDLLA, PLDGA, PMMA, PET, nylon, PE, PP, CAB and PEEK, while in other embodiments, the particulate comprises a silica material with or without an acrylic polymer. The thickening agent can assist in providing a suitable viscosity for the adhesive as it flows through the catheter to a target site.

In some embodiments, the chosen adhesive can also be mixed with one or more polymerization inhibitors, which could be, for example, an anionic or a free-radical polymerization inhibitor. Anionic polymerization inhibitors can include soluble acidic gases such as sulfur dioxide, or a biocompatible acid including, but not limited to, acetic acid, sulfuric acid, sulfonic acid, hydrochloric acid, phosphoric acid, carboxylic acid, nitric acid, or combinations thereof. In some embodiments, the acid can be from 0.01% to about 10% by weight, such as between about 0.01% and 1% by weight. Free-radical polymerization inhibitors include hydroquinone, t-butyl catechol, hydroxyanisole, butylated hydroxyanisole and butylated hydroxytoluene. The addition of one or more polymerization inhibitors such as a biocompatible acid helps to change the curing rate of the adhesive to prevent the adhesive from sticking prematurely to the catheter and prevent premature curing of the adhesive prior to binding to the vein wall. In some embodiments, the acid helps to delay the curing and/or polymerization of the adhesive to prevent the glue from sticking to sections of the catheter.

One skilled in the art will appreciate that multiple compositions of adhesive mixtures can be used in accordance with the embodiments described herein. In one embodiment, a composition of adhesive comprises from about 0.01 to about 50.0 weight percent of cyanoacrylate polymer, from about 0.01 to about 50.0 weight percent of a thickening agent selected from the group consisting of cyanoacrylate polymer, cyanoacrylate oligmer and biocompatible polymers, and from about 0.01 to about 10.0 weight percent of a biocompatible acid.

In some embodiments, the adhesive can also include a therapeutic agent such as an anti-inflammatory agent, an anti-infective agent, an anesthetic, a pro-inflammatory agent, a cell proliferative agent, or combinations thereof.

In some embodiments, the medical adhesives, such as the cyanoacrylate adhesives, can have select properties. In some embodiments, the medical adhesives can have a setting time of between about 5 to 60 seconds. The medical adhesives can also have a viscosity of between about 40 to 3000 cp. In some embodiments, the viscosity could be at least about 500 cp, at least about 1,000 cp, at least about 1,500 cp, at least about 2,000 cp, at least about 2,500 cp, or more. In some embodiments, the viscosity could be no more than about 2,000 cp, no more than about 1,500 cp, no more than about 1,000 cp, no more than about 500 cp, no more than about 300 cp, or less. One skilled in the art will appreciate that the type of adhesive is not limited to these particular characteristics, and that other adhesives having different properties may also be applicable.

Additional Embodiments Related to the Vein Closure System

In additional embodiments, a vein closure system is described that does not require capital purchases for a radiofrequency device or laser box. Simple and non-invasive methods of using the vein closure system are provided, and in some embodiments, the methods do not require application of a tumescent anesthesia or wearing compression stockings. The acceptance by and demand from patients of the vein closure system described herein will be much higher over existing devices and techniques.

In some embodiments, the closure system comprises at least two major components. One is a vein closure device which precisely delivers an adhesive to the abnormal saphenous vein under ultrasound guidance. The other component is a unique intravascular adhesive which allows for co-aptation and closure of the abnormal saphenous vein in a flattened, closed position. In other embodiments, the closure system comprises three major components. The first is a vein closure device which precisely delivers an adhesive to the abnormal saphenous vein under ultrasound guidance. The second is a unique intravascular adhesive which allows for co-aptation and closure of the saphenous vein just distal to the Superficial Femoral Vein Junction, such as within about 5 cm, 4 cm, 3 cm, 2 cm, 1 cm, or less in a flattened, closed position. The third is a solution that can have adhesive and/or sclerosing properties which allows for co-aptation and closure of the rest of the saphenous vein to alter the vein such that blood flow is prevented therein.

The Vein Closure Device

In some embodiments, the vein closure device which delivers the vein-occluding substance, e.g., an embolic adhesive, comprises three components. The first component is an outer catheter or introducer sheath that allows for placement under precise ultrasound guidance into the saphenous vein from as low a position as possible in the greater saphenous vein or lesser saphenous vein. The vein closure device is also configured for precise distal tip placement into the vein to be occluded. In some embodiments, the sheath is available in multiple size ranges and includes ID of 3 fr-7 fr and a length from 25 cm to 100 cm depending on the placement site. In some embodiments, the sheath is echogenic under ultrasound observation and therefore can be precisely placed below the sapheno-femoral junction. The sheath can have multiple graduations, as well measurement markings that indicate increments along the sheath, such as 0.2, 1, 2, or 5 cm increments. The graduations and markings assist in providing precise, monitored pull-back motions along the saphenous vein.

The second portion of the vein closure system is an introduction or inner catheter for the vein-occluding substance or adhesive. The inner catheter can be multiple sizes, such as from 3 fr-7 fr and include lengths of between about 25 cm to 100 cm to match the introduction sheath size ranges. In some embodiments, the inner catheter can be longer than the introduction sheath to allow the inner catheter to extend from a distal end of the introduction sheath. In one embodiment, one or both of the inner catheter and the introducer sheath are made of materials such as PTFE, ePTFE, PFA, FEP, or similar polymeric materials that will provide for negligible (if any) adhesion to the vein-occluding substance. In some embodiments, the inner catheter has an echogenic tip that assists in advancement through the introducer sheath. The inner catheter can be attached to the introducer sheath, such as by luer lock or other locking mechanism. The inner catheter protrudes from the introduction sheath at its distal end approximately 0.5-10 cm. and is visible under ultrasound due to its echogenic tip. The inner catheter is used for precise delivery of a vein-occluding substance into the vein for co-apting and occluding the vein into a flattened configuration. In some embodiments, the outer catheter and/or inner catheter can be coupled to or extend from a syringe designed to dispense a vein-occluding substance.

Glue Gun and Adapter

The third portion of the vein closure system is the glue gun or other adhesive introducing device that attaches to the inner catheter. In some embodiments, the adhesive introducing device is a manual liquid dispenser gun that can dispense an adhesive into a vessel with control and accuracy. One such dispenser gun is disclosed in U.S. Pat. No. 6,260,737 to Gruendeman et al., which is incorporated by reference herein in its entirety. Other embodiments of the glue gun are discussed in more detail below.

Additional embodiments are provided that are directed to a vein-occluding substance dispenser adapter, such as a glue gun, and associated components. In some embodiments, a glue gun is provided that is mateably attachable to a dispensing catheter or syringe by an adapter. The adapter can advantageously convert, for example, a conventional industrial glue gun for medical use, such as described herein while being properly sterilized as well.

FIGS. 22-32 illustrate a glue gun system configured to assist in the dispensation of a vein-occluding substance, according to some embodiments of the invention. FIG. 22 illustrates a side view of a glue gun and adapter system including an adapter 1, a glue gun 2, and a plunger 3 according to one embodiment. The adapter 1 includes an adapter lock end 4 with collars or flanges 25 that allow the adapter 1 to be fixed to the glue gun 2 via a holding segment 33. The adapter 1 further includes a syringe lock end 5 that allows the adapter 1 to be fixed to a syringe 36.

The glue gun 2 includes a handle 31 and a pull trigger 12. The pull trigger 12 is used in connection with internal mechanisms of the glue gun 2 (shown in FIGS. 33 and 34 and described further below) and the plunger 3 to provide controlled dispensation of a vein-occluding substance through syringe 36.

The plunger 3 comprises a solid rail-like segment that extends from outside the body of the glue gun 2 and through the internal body of the glue gun 2. The plunger 3 includes teeth that work in conjunction with a spring pawl mechanism (shown in FIG. 34) to lock the position of the plunger 3 and provide controlled dispensation of glue. The distal end of the plunger 3 makes contact with the proximal end of the syringe 36 such that the plunger 3 is capable of pushing the syringe to dispense a vein-occluding substance such as an adhesive.

FIG. 23 illustrates a perspective view of the adapter 1 in FIG. 22. The adapter 1 includes an adapter lock end 4, a syringe lock end 5, a holding slot 6 and a hollow body 7.

The adapter lock end 4 includes one or more collars or flanges 25 that are receivable into a holding segment of the dispenser gun upon rotation. The adapter lock end 4 is configured such that upon rotation of the adapter 1, the flanges 25 are received in and secured in the holding segment 33. In addition, the adapter lock end 4 includes an opening or slot (shown in FIG. 25) through which the distal end of the plunger 3 can be inserted.

The syringe lock end 5 includes a holding slot 6 for receiving a syringe 36 and an opening 41 through which the plunger 3 can pass. As shown in FIG. 23, the holding slot 6 is shaped like a barrel-wing. To secure a syringe to the syringe lock end 5, a proximal end of a syringe can be introduced into the holding slot 6. In some embodiments, the proximal end of the syringe can be barrel-wing shaped such that when the syringe is introduced to the syringe lock end 5, the syringe comes into contact with walls 34 of the holding slot 6. The syringe can then be rotated so that it is securely received in the holding slot 6. One skilled in the art will appreciate that the holding slot 6 and the proximal end of the syringe need not be shaped similarly. Nor is it necessary for the holding slot 6 to be barrel-wing shaped; any shape is suitable so long as it can receive a syringe end prior to rotating and securing of the syringe.

The hollow body 7 of the adapter 1 is designed to receive the syringe plunger 3 as it moves transversely substantially along a longitudinal axis of the hollow body 7 during injection. In some embodiments, the length of the hollow body 7 of the adapter is between 2 and 5 inches. The hollow body can be circular, elliptical or any other shape suitable for receiving the plunger 3. The diameter of the hollow body 7 can be, in some embodiments, between 0.5 and 1.1 inches.

FIG. 24 illustrates a front perspective view of the adapter 1 in FIG. 22, including the opening 41 through which the plunger 3 can be received. Also shown are walls 34 of the syringe lock end 5. The walls 34 are shaped such that upon initial entry of a syringe into the syringe lock end 5, surfaces of the syringe 36 are placed into contact with the walls 34. Upon rotation of the syringe 36, the syringe 36 can be locked into place in the holding slots 6.

FIG. 25 illustrates a rear perspective view of the adapter 1 in FIG. 22, including the adapter lock end 4 and flanges 25 receivable in the holding segment 33 of dispenser gun 2. Also illustrated is hole or opening 9 through which the plunger 3 can pass during the injection of vein-occluding substance.

FIG. 26 illustrates a cross-sectional view of the adapter 1 and its hollow body 7. From this view, it is possible to see the adapter 1 as having at least two separate diameters, an inner diameter (formed at the openings to the hollow body 7) and an outer diameter (formed in the hollow body 7 itself). In some embodiments, the inner diameter is between 0.5 and 0.9 inches, while the outer diameter is between 0.7 and 1.1 inches.

FIG. 27 illustrates a side view of a glue gun system including an adapter 1, a glue gun 2, and a plunger 3 according to another embodiment. The system includes an adapter lock end 4 and a syringe lock end 5 having a syringe 36 attached thereto. In contrast to the system in FIG. 22, the glue gun system in FIG. 27 does not include an adapter lock end 4 having an exposed collar or flange that is placed in a holding segment of the gun 2. Instead, the adapter lock end 4 includes a flange 25 (shown in FIG. 29) that mates with the glue gun 2 and remains unexposed upon final assembly.

FIG. 28 illustrates a side view of the glue gun and adapter system of FIG. 27 including the adapter 1, the glue gun 2, the plunger 3, and in addition, a delivery catheter 200. In some embodiments, the delivery catheter 200 includes an outer catheter surrounding an inner catheter. The delivery catheter 200 extends from the distal tip of the syringe 36 and is designed to provide access to a target site within a vessel interior.

FIG. 29 illustrates a perspective view of the adapter 1 in FIG. 27 having an adapter lock end 4, a syringe lock end 5, a hollow body 7 and a fit-in notch 8 located near the adapter lock end 4. The fit-in notch 8 is capable of receiving a mateable collar or flange located on the glue gun 2 that will lock the adapter 1 to the glue gun 2 upon rotation of the adapter.

FIG. 30 illustrates a front perspective view of the adapter 1 of FIG. 27, including the syringe lock end 5. An opening 41 located on the syringe lock end 5 is also shown. The opening 41, which is configured to receive a dispenser plunger 3, is T-shaped in some embodiments, although single slit, “I”, arcuate, or other shaped openings are also possible. The advantage of the T-shaped opening 41 is that it can provide better guidance for a dispenser plunger 3 that is received through the syringe lock end 5, as the T-shaped opening provides specific paths along the “T” shape for the plunger 3 to move. The T shape can also add strength to the plunger 3, such as in the longitudinal direction, for more efficient dispensing. The T shape also could add stability to the plunger 3 in the transverse direction to increase its buckling strength so that it will be less likely to buckle during the dispensing of high viscosity materials.

FIG. 31 illustrates a rear perspective view of the adapter 1 of FIG. 27, including the adapter lock end 4. The adapter lock end 4 includes its own T-shaped opening 9, similar to the T-shaped opening 41 in the syringe lock end 41, through which dispenser plunger 3 can pass.

FIG. 32 illustrates a cross-sectional view of the adapter 1 of FIG. 27 and its hollow body 7. The adapter 1 includes a central lumen 7 with open proximal and/or distal ends and designed to allow the syringe plunger 3 to move through during the injection process. The adapter 1 also can optionally include one, two, or more side lumens 10 defined between walls 70 and 72, which can provide the adapter 1 with a reduced weight, which can be beneficial in some circumstances. In some embodiments, the side lumens 10 define a closed free space volume that is at least about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or more of the entire enclosed volume between walls 70, 72. By providing an adapter with reduced weight, this allows for improved handling, reduced weight, and cost efficiencies for manufacturing purposes. In other embodiments, the adapter 1 can include regions besides or in addition to the second hollow space 10 that are removed or cut-out of the adapter 1 to provide additional weight reduction.

FIG. 33 illustrates an adapter 1 and glue gun 2 prior to assembly. In some embodiments, the glue gun 2 includes extensions 66 that enclose an open space 67 for receiving the adapter lock end 4 of the adapter 1. While the adapter lock end 4 is placed in the open space 67, the extensions 66 of the glue gun 2 enclose the fit-in notch 8 of the adapter 1, thereby forming a secure connection between the adapter 1 and glue gun 2, as shown in FIG. 34.

FIG. 34 illustrates the adapter 1 and glue gun 2 of FIG. 33 following assembly. Included in the assembly within the hollow body 17 of the glue gun are plunger 3 with teeth 16, stopper 11, spring mechanism 15 including spring pin 13 and spring pawl 14, plunger release button 18, floating gripper 19, plunger pocket 20 and spring stop 21.

As shown in FIG. 34, the assembly includes a glue gun 2 having a trigger 12 for controlling the dispensation of glue from the gun. The trigger 12 of the glue gun is integrated with the gun body by a spring pin 13, which is part of a spring mechanism 15. The spring mechanism 15 also includes a spring pawl 14 designed to interact with teeth 16 of the plunger 3 to precisely lock the position of the plunger. Movement of the spring pawl 14 is controlled by the trigger 12. Upon pressing or clicking of the trigger, the spring pawl 14 is adjusted to allow one or more teeth 16 of the plunger 3 to move forward through the adapter 1 and press against a syringe (not shown) to dispense a glue or adhesive. To prevent the rearward movement of the plunger 3 after clicking the trigger, a floating gripper 19 is provided that engages with the plunger 3 to stop rearward movement by frictional force. Plunger pocket 20 can allow movement (both forward and backward) of floating gripper 19 in the pocket. During the forward movement of the plunger 3, the floating gripper 19 moves with the plunger 3 (because of the friction between them) assisted by the plunger pocket 20. After the trigger is released and the plunger 3 (with the floating gripper 19) moves backward, the plunger pocket 20 sets the limit for the movement of the plunger 3. The plunger release button 18 allows the disengagement between the plunger 3 and the spring pawl 14. Pushing the plunger release button 18 will move the spring pawl 14 downward and release the plunger 3 from the spring pawl 14. Then the plunger 3 will be free to move in either backward or forward directions.

To limit the effect of the spring mechanism 15 and restrict the forward displacement of the plunger teeth 16, the spring mechanism 15 is accompanied by a stopper 11. The stopper 11 serves as a physical barrier to the movement of the spring mechanism, thereby providing for greater control over dispensation of the glue or adhesive.

FIG. 35 is a front view of the glue gun 2 that illustrates the gun hollow body 17. Among the mechanisms within the gun hollow body 17 includes the plunger 3, which is displaced within the hollow body by the pull of the gun trigger.

The embodiments of the glue gun system described in FIGS. 22-35 are designed to deliver precise amounts of adhesive or similar vein-occluding substance and can be used with the methods described above. By providing greater control over the dispensation of vein-occluding substance, such as by using a spring mechanism 15 including spring pawl 14 and stopper 11, the glue gun system can deliver the vein-occluding substance continuously or in discrete injectable quantities, such as 0.1 ml to 1.0 ml per injection, thereby advantageously reducing the risk of overflow and back-clogging of the delivery system. The amount of vein-occluding substance used can depend on the size of the vein, the compression pressure, and surrounding environment. The glue gun will allow for exact increments of adhesive to be extruded or discharged from a catheter. This will allow a vein to be sealed shut at multiple sites along its length.

Deployable Occlusion Device

Embodiments are now described that relate to components of a venous occlusion system comprising a deployable occlusion device. FIG. 36 schematically illustrates components that can be used in a venous occlusion system, according to one embodiment of the invention. The system can include, for example, a deployable occlusion device 100 for insertion into a desired location within a vein; a catheter 200 which can be a tubular member for delivering the occlusion device 100 as well as serving as a conduit for delivery of one or more substances for closing the vein; and an injector 300 that can be coupled to the catheter 200 and actuating the substance into the vein via the catheter.

FIGS. 37A-D illustrate various views of one embodiment of a vascular occlusion device 100, according to one embodiment of the invention. Although certain particular embodiments of an occlusion device will be described in detail herein, one of skill in the art will appreciate that any of a variety of occlusion devices can be utilized in the system of the present invention. In some embodiments, the occlusion device can be transformable from a first, reduced cross-sectional configuration for transluminal advance to the deployment site, to a second, radially enlarged or transversely enlarged configuration for occluding the vein. Transformation from the reduced configuration to the enlarged configuration can be accomplished in a generally radially symmetrical fashion, or in an elliptical, or planar fashion, each of which can accomplish the result of achieving localized closure of the tubular structure such as a vein in which the device is deployed. However, in some embodiments, the occlusion device 100 can be a vein-occluding substance, e.g., a bolus of glue, as will be described further below.

Transformation of the occlusion device may be accomplished in any of a variety of ways, such as by releasing a restraint on a frame which is biased in the direction of the enlarged configuration. Alternatively, the occlusion device may be transformed to the enlarged configuration under active force, such as by axial shortening to achieve radial expansion. As a further alternative, occlusion devices for use with the system of the present invention may include detachable inflatable balloons, open cell or closed cell foam, sponge, embolic coil meshes having either a randomized or predetermined pattern, or other structures depending upon the desired clinical performance. The occlusion device may be provided with one or two or more tissue anchors or barbs, for engaging the vessel wall, or other anti-migration surface features such as a roughened or adhesive surface, and/or enhanced surface area for contact with the vessel wall in a manner sufficient to inhibit migration.

FIG. 37A is a perspective view of an occlusion device 100 that includes a frame portion 102 and a barrier portion 106. The occlusion device is shown in a reduced, low crossing profile configuration for delivery, such as within a catheter 200. The frame portion 102 as shown has a proximal end 103 and a distal end 105, and can include at least 2 or 3 or 6 or 8 or more interconnected struts 106 as shown.

The frame 102 may have a wide variety of wall patterns depending on the desired clinical result, or have a continuous sidewall in some embodiments. In the illustrated embodiment, the wall pattern comprises a generally sinusoidal framework including a plurality of proximally facing apexes 112 and distal apexes 110 interconnected by a plurality of struts 114. This can be clearly seen, for example, in FIG. 39B.

The frame portion 102 can be made of a metal, such as stainless steel, or a shape memory material such as, for example, nitinol or elgiloy. However, in some embodiments, the frame portion 102 may be made of a shape memory polymer or biodegradable material, such as, for example, poly(alpha-hydroxy acid) such as poly-L-lactide (PLLA); poly-D-lactide (PDLA), polyglycolide (PGA), polydioxanone, polycaprolactone, polygluconate, polylactic acid-polyethylene oxide copolymers, modified cellulose, collagen, poly(hydroxybutyrate), polyanhydride, polyphosphoester, poly(amino-acids), or related copolymers. In some embodiments, the frame portion 102 can be laser-cut out of a tube. If the frame portion 102 is biodegradable, it can be configured to fully degrade over a period of time depending on the desired clinical result and the properties of the vein-occluding substance (e.g., hardening or polymerization time of a glue), such as, for example, less than about 1 year, 6 months, 3 months, 1 month, 2 weeks, 1 week, 3 days, 1 day, 12 hours, 6 hours, 3 hours, or less.

The barrier portion 104 can be sized, shaped, and attached to the frame 102 in a variety of ways such that when deployed in an expanded configuration in the blood vessel, the occlusion device 100 prevents blood flow through the vessel. In some embodiments, the barrier 104 is coupled to the frame 102 via sutures, adhesives, clips, or other form of attachment. The barrier 104 may be made of any appropriate biocompatible material suitable for occluding a vessel, such as a mesh. In some embodiments, the barrier 104 may be made of nitinol, elgiloy, Dacron®, Gore-Tex®, nylon, TFE, PTFE, ePTFE, peritoneum, subintestinal submucosa or other synthetic or biological membrane. Further materials that can be used for both the frame 102 and barrier 106 portions can be found, for example, in U.S. Patent Pub. No. 2007/0292472 A1 to Paul et al., which is hereby incorporated by reference in its entirety.

FIG. 37B illustrates a side view of the occluder illustrated in FIG. 37A. FIG. 37C illustrates a section through line A-A of FIG. 37B, showing the barrier 104 as well as frame 102. FIG. 37D is an end view of the device illustrated in FIGS. 37A-37C.

While the above occlusion device 100 is described as having a frame portion 102 and a barrier portion 104, various other occlusion devices to prevent blood flow through the vessel lumen are also within the scope of the invention, such as plugs, sponges, coils, adhesives, prothrombotic agents, and the like.

In the embodiment illustrated in FIG. 37A-37D, the axial length of the frame when in the compressed configuration is generally within the range of from about 5 mm to about 30 mm, or about 10 mm to about 20 mm in some embodiments. The outside diameter of the frame when compressed within the catheter is generally no greater than about 8 French, and preferably no greater than about 4 French in some embodiments. The maximum outside diameter of the occlusion device when in an unconstrained expansion is generally within the range of from about 2 mm to about 16 mm, or about 4 mm to about 12 mm in some embodiments.

FIGS. 38A-38D illustrates the occlusion device 100 of FIGS. 37A-37D in a deployed configuration. As noted above, the occlusion device 100 may be made of a shape memory material to facilitate self-expansion of the device from a reduced to an enlarged configuration. In other embodiments, the device 100 is balloon-expandable. As shown, the diameter of proximal end 103 of the device 100′ expands to greater than that of the distal end 105 in order to engage the vessel wall and occlude the vessel. In some embodiments, the diameter of the proximal end 103 expands to at least about 110%, 120%, 130%, 140%, 150%, 200%, or more of its diameter in an undeployed configuration. In some embodiments, the device 100 includes, such as on its proximal end 103, one or more retention structures for retaining the device 100 in the vessel wall. In some embodiments, a plurality of barbs or other anchors are provided, for engaging adjacent tissue to retain the occlusion device 100 in its implanted position and to limit relative movement between the tissue and the occlusion device 100. The anchors are provided on one device 100. The anchors are provided on one or more of the struts 106, or other portion of frame 14. In some embodiments, every strut, every second strut, or every third strut are provided with one or two anchors each, or more. The anchor can be in a form or a barb, spike, or other appropriate configuration for securing the occlusion device 100 to the vessel wall, as illustrated in greater detail in FIG. 40 below.

FIGS. 39A-39B illustrate an embodiment of the frame 102 portion of the delivery device described above in connection with FIGS. 2A-3D in its undeployed (FIG. 39A) and deployed (FIG. 39B) configurations with the barrier portion 104 omitted for clarity.

FIG. 40 is a side cross-sectional view of an occlusion device 100 in an expanded configuration and implanted within vessel 400. As previously described, the occlusion device 100 has a proximal end 103, distal end 105, and one or more anchors 112 to limit relative movement between the occlusion device 100 and the vessel wall 400. The device 100 may have any number of anchors depending on the desired clinical result, such as at least 1, 2, 3, 4, 5, 6, or more anchors.

FIG. 41 is a longitudinal cross-sectional view of an occlusion device 100 such as that illustrated in FIG. 40, and in an undeployed configuration within a delivery catheter 200. Delivery catheter 200 includes an inner catheter member 204 and an outer catheter member 202. Occlusion device resides within a lumen of outer catheter member 202. Relative movement of inner catheter member 204 relative to outer catheter member 202, such as retraction of outer catheter member 202 relative to inner catheter member 204 or pushing of inner catheter member 204 distally relative to outer catheter member 202 can facilitate deployment of the occlusion device 100 within the vessel 400. Inner catheter member 204 may comprise a concentric tube, a push wire, or other structure capable of transmitting a deployment activating force.

Occlusion device 100 as shown is releasably attached to a detach mechanism 120 that allows for retraction and repositioning of the occluder member prior to deployment. The detach mechanism 120 can be any of a wide variety of mechanisms to provide releasable detachment, for example, mechanical, chemical, or electrolytic detachment. Some examples of mechanical detach mechanisms include a snare, suture loop, clip and the like. The proximal end of the catheter preferably includes a luer lock or similar mechanism for coupling to a syringe or other injector for inserting a vein-occluding substance into the vein.

In some embodiments, after the occlusion device is deployed, a vein-occluding material such as a sclerosing agent is injected into the vein. The purpose of the vein-occluding material can be to partially or completely destroy the endothelial cells lining the venous lumen, expose the subendothelial collagen fibers within the vein, and ultimately form a fibrous cord. After the lining of the vein is damaged the vein can be forced closed by the use of compression stocking worn by the patients. Over time the damaged vein scars upon itself creating a completely closed vein. Endothelial damage is preferably as complete as possible, because otherwise, thrombus will form and layer endoluminally. The presence of a deployed occlusion device 100 advantageously prevents distal embolization of the vein-occlusion substance distally past the occlusion device 100. Any vein-occluding material can be used depending on the desired clinical result.

A wide variety of vein-occluding substances can be used. In some embodiments, the substance can include an adhesive such as cyanoacrylate, e.g., 2-octyl cyanoacrylate, and/or a sclerosing agent such as hypertonic saline, sodium tetradecyl sulfate, chromated glycerol, tetracycline, talc, bleomycin, or polydocanol. Other adhesives that can be used include a biological glue such as a bovine serum albumin-gluteraldehyde combination (e.g., BIOGLUE, Cryolife, Atlanta, Ga.). In some embodiments, a foam generated from, for example, one or more of the above components can be used to enhance ablation and closure of the vein. The viscosity and air bubble mixture can also be controlled taking into account the desired clinical result. Ultrasound or other imaging modalities such as, for example, fluoroscopy, CT, or MRI can be used to observe and control distribution of the vein-occlusion substance. In some embodiments, foam or other micro-bubbles within the vein-occlusion substance can also serve as ultrasonic contrast. Further examples of agents, methods, and devices for vein closure that can be used as well are described, for example, in U.S. Pat. No. 4,039,665 to Foley, U.S. Pat. No. 5,676,962 to Garrido et al., U.S. Pat. No. 6,572,873 to Osman et al., U.S. Pat. No. 6,726,674 to Leu, U.S. Pat. No. 7,314,466 to Lary et al., and U.S. Patent Pub. No. 2003/0206864 A1 to Mangin, all of which are hereby incorporated by reference in their entireties. In some embodiments, the invention can be practiced using a cyanoacrylate based echogenic adhesive, visible under conventional ultrasound.

FIGS. 42-44 illustrate a cross-section of occlusion device 100 (with barrier portion 104 not shown for clarity) in varying stages of deployment caused by relative movement of inner catheter 204 relative to outer catheter 202.

Using the systems and methods described herein provides little to no risk of injury to surrounding nerves or tissue, because the length of the treated vessel can be clearly identified without unnecessary overtreatment. This is in contrast to many other procedures which require, for example, that a catheter is placed superior to nerves which may be juxtaposed to the saphenous vein.

The vein closure system allows for a simple treatment for veins, such as abnormal refluxing varicose veins. The vein closure system includes the delivery system and the unique intravascular adhesive. The procedure is less invasive, less painful, more effective and easier to recover from compared to existing treatments.

Although this application has been disclosed in the context of certain embodiments and examples, it will be understood by those skilled in the art that the present application extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the application and obvious modifications and equivalents thereof. Additionally, the skilled artisan will recognize that any of the above-described methods can be carried out using any appropriate apparatus. Further, the disclosure herein of any particular feature in connection with an embodiment can be used in all other disclosed embodiments set forth herein. Thus, it is intended that the scope of the present application herein disclosed should not be limited by the particular disclosed embodiments described above. 

What is claimed is:
 1. A method for treating a vessel, the method comprising: inserting a catheter into the vessel; positioning a distal end of the catheter at a location within the vessel; creating an occlusion in the vessel distal to the location within the vessel; after creating the occlusion in the vessel, actuating a control of an injector, the injector coupled to a syringe that is coupled to a proximal end of the catheter, wherein actuation of the control causes a movable wall to move within the syringe to dispense a vessel-occluding substance from the syringe and directly against the occlusion in the vessel; applying external pressure to the location of the vessel to compress the vessel and coapt the vessel to occlude the vessel via the vessel-occluding substance dispensed from the catheter; and removing the catheter from the vessel.
 2. The method of claim 1, wherein the location is a first location, and wherein the method further comprises, after applying external pressure to the first location: positioning the distal end of the catheter at a second location within the vessel proximal to the first location; actuating the control of the injector to dispense the vessel-occluding substance from the syringe and into the vessel at the second location via the catheter; and applying external pressure to the second location of the vessel to compress the vessel and coapt the vessel to occlude the vessel at the second location via the vessel-occluding substance dispensed from the catheter at the second location.
 3. The method of claim 1, wherein the location is a first location and the occlusion is a first occlusion, and wherein the method further comprises, after applying external pressure to the first location: creating a second occlusion in the vessel proximal from the first location and distal to a second location within the vessel; positioning the distal end of the catheter at the second location within the vessel proximal to the second occlusion; actuating the control of the injector to dispense the vessel-occluding substance from the syringe and directly against the second occlusion in the vessel; and applying external pressure to the second location of the vessel to compress the vessel and coapt the vessel to occlude the vessel at the second location via the vessel-occluding substance dispensed from the catheter at the second location.
 4. The method of claim 1, wherein the control comprises a pull trigger, and wherein actuating the control comprises moving the pull trigger towards a handle of the injector.
 5. The method of claim 4, wherein the pull trigger is mechanically coupled to a plunger configured to contact the syringe, wherein movement of the plunger in a direction away from the handle causes delivery of the vessel-occluding substance from the syringe.
 6. The method of claim 4, wherein moving the pull trigger in a first direction causes a ratcheting mechanism to engage teeth defined by the plunger and move the plunger in a second direction different than the first direction.
 7. The method of claim 4, wherein actuating the control comprises moving the pull trigger to move the movable wall a predetermined distance towards a distal end of the syringe and deliver a bolus of the vessel-occluding substance from the syringe and the catheter into the vessel.
 8. The method of claim 1, wherein actuating the control causes the injector to deliver a predetermined volume of the vessel-occluding substance, the predetermined volume of the vessel-occluding substance being about 0.05 mL to about 0.5 mL.
 9. The method of claim 1, wherein actuating the control causes the injector to deliver a predetermined volume of the vessel-occluding substance, the predetermined volume of the vessel-occluding substance being about 0.1 mL to about 0.2 mL.
 10. The method of claim 1, wherein actuating the control causes the injector to deliver the vessel-occluding substance from the catheter in a volume sufficient to advance the vessel-occluding substance proximally around the distal end of the catheter between a sidewall of the catheter and a wall of the vessel.
 11. The method of claim 1, wherein the injector defines a holding slot configured to receive flanges of the syringe and secure the syringe to the injector.
 12. The method of claim 11, wherein the syringe and the injector share a common axis when the flanges of the syringe are received within the holding slot.
 13. The method of claim 1, wherein the injector comprises an adapter and a glue gun portion, wherein the glue gun portion comprises a handle and is configured to be attached to the adapter, and wherein the adapter is configured to couple the syringe to the glue gun portion.
 14. The method of claim 1, wherein the catheter comprises a length sufficient to extend from a distal superficial leg vein of a patient to a superficial femoral vein junction of the patient.
 15. The method of claim 1, wherein the catheter is coupled to a distal end of the syringe via a luer lock connection.
 16. The method of claim 1, wherein the catheter comprises an echogenic tip portion, and wherein positioning the distal end of the catheter at the location within the vessel comprises verifying, using ultrasound identification of the echogenic tip portion of the catheter, that the distal end of the catheter is at the location of the vessel.
 17. The method of claim 1, wherein the vessel-occluding substance comprises cyanoacrylate.
 18. The method of claim 1, wherein applying external pressure to the location of the vessel comprises applying a compression element configured to externally compress at least a portion of the vessel. 